Various embodiments relate to elevator bail link systems and methods wherein the overall length and/or capacity (e.g., tonnage capacity) of an elevator bail or link system may be changed.
The hoisting system of a drilling rig includes a set of elevator bails or links which comprise the linkage between the traveling block/top drive and the hoisting elevator.
In a top drive hoisting system, these elevator bails/links are also equipped with a link tilt system mechanically connected to the bails. The link tilt system can tilt the connected bails/links during rig operations, for example, toward the v-door, mouse-hole, and/or derrick racking board while tripping drill pipe or running casing.
During the drilling of an oil and gas well, it is often necessary to change the configuration of the elevator bails, typically due to the need for additional length and/or tonnage capacity. For instance, the rig may utilize elevator bails with a 9 foot (7.7 Meter) length and a 350 Ton (317,514 Kilograms) capacity during drilling/tripping operations with drill pipe, then change to 18 foot (5.5 Meter) 500 Ton (453,592 Kilograms) bails during casing running operations to provide clearance for fillup tools, casing running tools, cementing heads, and other devices as well as load capacities for casing strings which are generally heavier than the drill string.
In prior art systems the process of changing elevator bails typically requires disconnecting the link tilt assembly and possibly reconnecting the link tilt assembly to the “casing” set of bails, depending on whether link tilt is needed for the casing operation. In addition, after the casing is run the reverse generally occurs, i.e. the casing bails are removed and the drilling/tripping bails are re-installed.
Prior art methods of changing bails is time consuming, and typically occurs at a point when the rig is “out of the hole” so that the rig generally cannot perform other operations during the changing of bails. Consequently no progress is being made on the well at this point, commonly referred to as “nonproductive time”, and may typically take one or more hours, for example 1 or more hours on a land rig and 3 or 4 or more hours on a deep water rig. This time frame can currently cost the operator increased rig time costs, which can range from approximately $2,000/hour on a land rig to as much as $75,000/hour on an ultra deepwater rig. Also, as there is no drill pipe or casing in the well, the well is susceptible to either flow of hydrocarbons or loss of fluid in the well, which is difficult, and may be impossible to mitigate without drill pipe or casing being in the well acting as a conduit for transporting weighted fluids into the well at a point low enough to address the problem flow of hydrocarbons or loss of fluid in the well.
In addition the process of disconnecting and potentially reconnecting the link tilt mechanism can be dangerous in that it involves personnel working at heights on elevated platforms, work baskets, or man riding hoists, removing and potentially reconnecting hardware that could be dropped to the rig floor, and maneuvering the long bails into and out of the rig floor area.
There is thus a need in the art for a system and method for interchanging elevator bails or links, for addressing one or more of the above identified difficulties in the prior art, which include but are not limited to such as performing different oil rig operations, that is quick and efficient, and to lessen non-productive rig time and associated cost.
There is also a need in the art for a system and method for interchanging elevator bails or links that will mitigate or lessen the nonproductive time which can result in flow of hydrocarbons or loss of fluid in the well that occurs during non-productive rig time.
There is also a need in the art for a system and method for interchanging elevator bails or links for performing different oil rig operations that is safer for rig personnel.
In the prior art, for example U.S. Pat. No. 6,520,709, the art requires assembly horizontally on the warehouse floor or rig deck of an elevator link system with different length components, with mechanical or human assistance to align the sections or components, and therefore does not accomplish the objective of safer and more efficient means of changing elevator bail configurations at the rig floor. In addition the prior art configuration does not meet industry specifications for load carrying capacities (API 8c).